Software Development: The 90/90 Rule

What I call the 90/90 Rule of Software Development usually bites new inexperienced developers in the ass. It’s the concept that there’s the first 90% of building the app… and then there’s the second 90%. Let’s talk about it.

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24 Comments on “Software Development: The 90/90 Rule”

  1. I am react native developer. I want to start with iOS development for native development knowledge.

    You're videos are very informative. Thank you

  2. Couldn't agree more sean keep the good content up, ow and nice beard your growing

  3. Sean, I need help my son and I are struggling. could you please help.
    my personal email is once read could you delete this comment and contact me.

    Kind Regards

  4. Do you think we have to support very old devices like iPhone 5 or 4s ? I have too many problems when I want to support iPhone Xs Max and also iPhone 4s. What do you think Sean?

  5. I really want to know how you deal with 2nd 90 percents. Often times I end up left with a mess of code and unresolved bugs. It would be great to hear some advice from experienced dev like you. Thanks for your video anyway.

  6. When it comes to Error Handling and Edge Cases, I just do them first, or at least error handling. You have to just assume everything is going wrong all time and handle those conditions first. This way you reverse the 2nd 90% with the first.

  7. I released my first iOS app in 2013, as a hobbyist. Figuring out signing and getting the app into the App Store was a nightmare.

  8. This a great thing to be mindful of Sean, good tips. Also +1000000000 for advocating developers take a11y seriously.

  9. I really loved this as you have have explained the actual reality that every client has to understand.

    When i started my career in mobile development I learned that developer will never release his application coz he will always find something more innovative and more improvements in his own code and you have to push developer to release the same code. TDD is something which is amazing in development if you are used to it you will enjoy the benefits.

    Keep helping others. ?

    But i really want to connect with you and understand how you manage your time.. ??

  10. I resort to splitting app development into two phases and urge my clients to pay ? also apply 80/20 rule of total delivery time to develop modules and UAT .

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